Finally completed my powder toy processor.

LoadSaveBlock(4260);

Commands are input on the "Input" section. The first input (Marked with the arrow) is the highest significant bit of the command. (Ie. the one in the below number)
1000

Commands with no arguments.
Code - What it does
0000 - No Operation
0010 - Send stop command
1101 - Adds register A & B together and puts the result in C
1110 - Subtracts A and B (A-B) and stores the result in C

Commands that which require an argument take two clock cycles to gather/process the info.
For example if I want to load ram slot 2 into register A. I would first use.
1001 - Load ram into register A
Then once the clock cycle has completed. I would then use.
0010 - Binary for 2
Another clock cycle should pass and the information from ram slot 2 will be in register A.

The following commands have one argument, this is the constant to load into the register.
Code - What it does
0001 - Load constant into register A
0011 - Load constant into register B

The following commands have one argument, this is the position of ram in which to load/store data.
Code - What it does
10XX - Load data from ram slot into register XX
01XX - Store register XX into ram slot
XX01 - Register A
XX10 - Register B
XX11 - Register C

Following codes do not work & will probably cause issues.
1000
0100
1100
1111 (A 2 bit decoder here would give an extra 2 commands)

Edit reason: Revised ram section.
Edit reason: Added subtraction (triclops200)

Issues/Notes
Ideally you would want some kind of stack to be automatically placing commands onto the processor each clock cycle.
I also believe there is an issue when loading data from ram into register C (It sometimes causes ram slot 0 to take incorrect data)

Triclops what do you mean?

Just a sec I'll mark some things and upload it.

Ok. The inputs have been marked. The one with the arrow is the highest significant bit. I'm going to edit the first post.